Method for the accurate weight casting of metal plates

ABSTRACT

A method for the accurate weight casting of metal plates and in particular, of copper anode plates includes tapping a liquid casting metal from a smelting furnace and collecting it in a relatively large vessel by measuring the weight in a differential weighing step as the dosed partial quantity is controlled and thereafter weighing a nominal weight of the metal melt for casting a single plate into a smaller vessel before it is poured into the mold and directing the finally weighed melt into the casting from the smaller vessel. The apparatus includes a trough arranged to receive the melt material from a furnace which is tilted to dispense a selected quantity and deliver it along the trough into a first large sized vessel which is supported on a differential weighing apparatus. The large sized vessel is then selectively tilted either to the left or to the right in order to pour a quantity of the melt into a smaller size vessel. The quantity poured is equivalent to the weight of the anode to be cast. The smaller size vessel also is supported on a differential weighing apparatus, and, when the required quantity of metal is filled into the small sized vessel, it is tilted to pour the material into a casting mold. Each small size vessel is associated with a casting wheel which has a plurality of molds with openings adajcent the periphery thereof and which are selectively aligned with the smaller size vessels in succession in order to receive a charge of the melt material.

United States Patent r191 Kreuz et al.

[ Mar. 11, 1975 METHOD FOR THE ACCURATE WEIGHT CASTING OF METAL PLATES [75] Inventors: Otto Kreuz, Duisburg; Stephan Raab, Essen, both of Germany [73] Assignee: Demag Aktiengesellschaft, Duisburg,

Germany 22 Filed: Sept. 8, 1972 211 Appl. No.: 287,471

Related US. Application Data [63] Continuation of Ser. No. 62,051, Aug. 7, 1970,

abandoned.

[30] Foreign Application Priority Data Primary ExaminerRobert D. Baldwin Attorney, Agent, or FirmMcGlew and Tuttle [57] ABSTRACT A method for the accurate weight casting of metal plates and in particular, of copper anode plates includes tapping a liquid casting metal from a smelting furnace and collecting it in a relatively large vessel by measuring the weight in a differential weighing step as the dosedpartial quantity is controlled and thereafter weighinga nominal weight of the metal melt for casting a single plate into a smaller vessel before it is poured into the mold and directing the finally weighed melt into the casting from the smaller vessel. The upparatus includes a trough arranged to receive the melt material from a furnace which is tilted to dispense a selected quantity and deliver it along the trough into a first large sized vessel which is supported on a differential weighing apparatus. The large sized vessel is then selectively tilted either to the left or to the right in order to pour a quantity of the melt into a smaller size vessel. The quantity poured is equivalent to the weight of the anode to be cast. The smaller size vessel also is supported on a differential weighing apparatus, and, when the required quantity of metal is filled into the small sized vessel, it is tilted to pour the material into a casting mold. Each small size vessel is associated with a casting wheel which has a plurality of molds with openings adajcent the periphery thereof and which are selectively aligned with the smaller size vessels in succession in order to receive a charge of the melt material.

4 Claims, 3 Drawing Figures PATENTED 1 i975 3,870,097

' SHEET 1 [If 2 I @111 w A i 20 I815 55 @751 ,2 18 12 9 l7 I f 27 X 17 --K/ Inventors arm LEEUZ STEP/MN 2M PATENT EB MARI 1 I975 sumanfz Fig. 2

Inventors arm KEEUZ STFPHAN e448 Maw w lrrom gs METHOD FOR THE ACCURATE WEIGHT CASTING OF METAL PLATES This is a continuation, of application Ser. No. 62,051, filed Aug. 7, 1970, now abandoned.

SUMMARY OF THE INVENTION This invention relates in general to a method for easting metal plates, and in particular to a new and useful method for the accurate weight casting of metal plates, in particular of copper anode plates.

One of thedifficulties in casting, particularly copper anode plates, is the control ofthe precise amount ofliquid metal for casting which is tapped from a smelting furnace, collected, weighed, and then poured into respective casting molds as a dosed partial quantity which is added in controlled timing steps in accordance with the differential weighing of the melt material. The dosing of the liquid metal is bound to the process of interrupting and releasing the casting flow of the melt. The discontinuity of flow is in the nature of the process. In fractions of secondsthere developed varying volumetric quantities of released casting metal. For copper anode plates the absolute size of the casting quantity is not of primary importance but the maintenance ofa selected weight value once chosen is very important. However, it is not possible either to make the pouring process so reproducible that an odd, yet uniform, quantity of casting metal flows into the casting mold each time. The reasons are to be found in a multiplicity of constantly changing physical values. In addition, the influence of the most economical production method also plays a complicating roll in deciding the ultimate manner in which the casting is to take place. The high production rate demanded makes short cycling times of the casting wheels, which are employed for indexing the various molds into association with a casting supply, mandatory. The uneven operation of the smelting furnace with its uncontrolable tapping flow must be converted into partial quantities of the same size and uniform cycling times. In view of'all these conditions, endeavors to arrive at acceptably close weight tolerances required complicated regulating circuits and required long regulating distances. The specialist in the field has, as a prototype, the known solution with a regulating circuit which begins with the determination of a tare weight. After the metal is tapped from the furnace, the actual weight is determined and the weight of the filled casting mold is superposed, as a parameter, to give a control influence impulse to a control instrument for the next tapping operation. This controls the casting time and the pouring ladles angle of inclination. However, it is only possible to obtain a control impulse from one or more measurements which have taken place earlier. Ultimately the result ofthe measurement of one operation is applied to the next following one which causes errors for several reasons. Sources of errors are temperature fluctuations of the casting metal, the degree to which the collecting vessel is filled, and the constantly repeating tare measurements. A determination of the gross weight can practically take place only when weighing operation with the metal level in motion is carried out. In any event the casting mold must be lifted from its bearings for weighing. Considering the weights of 4,000 kp per casting mold any measuring operation in such a system is associated with time losses and prevents the operation at short cycle times. From the standpoint of economical production therefore a measuring operation which greatly increases the production time is not warranted.

A discontinuous operating mode of the smelting furnaces is not desirable but it is hard to avoid. The discharging casting metal mixes incompletely with metal already present in the collecting vessel, and therefore, the parameter of the degree to which it is filled takes into account no temperature values. A control impulse triggering the accelerations and decelerations required for tilting the vessel forwardly and backwardly is constantly given Without consideration of the change of viscosity of the casting metal. Not all of the interferring values can be picked up in the known method and in addition the known methods must operate with long time intervals for obtaining the measuring values. Time is wasted due to the fact that the various test values can be obtained only as a function of the operating mode of the casting wheel containing the casting molds. Regulation to a desired nominal weight therefore, takes place with retardations so that several plates will be made with tolerances which exceed specifications. When the tolerance range is finally reached a new correction must be reckoned with because the initial values have meanwhile changed again. Then it is necessary for a new regulating process to start.

In accordance with the present invention, the above deficiencies are overcome and the accuracy of pouring is increased while the regulation operation is greatly simplified. In particular, less inertia power is required for regulating the sequence of movement of the molds with the casting wheel. The present invention includes a better method for the accurate weighing of the casting metal for forming the plates. The nominal weight of the metal plates is determined prior to the pouring of the casting metal into a casting mold regardless of the actual weight of a previously cast metal plate. This is done by weighing an absolutely setable partial quantity from a total quantity amounting to two or three times the partial quantity. The new method operates without measuring the tare or gross weight of the casting mold. This has been done by a realization that a cast metal plate can experience no further weight modification if it is already beyond tolerance range and therefore the best that can be done with it is to remelt it. The absolute tapping of a nominal quantity can be accomplished accurately enough by traditional means but it is particulary advantageous in this process of the invention to start from a small quantity which makes hitherto encountered inaccuracies which are involved in the releasing of the casting flow or in the stopping of the casting flow shrink to minimum values. It was found that it is advantageous to select the small quantity in order to avoid too great temperature losses on the one hand and also because it is suitable in order to reduce the great mass accelerations and decelerations which would have been required.

With the invention method, the total quantity, which is two or three times greater than the partial quantity, is replaced after the casting operation is concluded. The amount of replacement is determined by absolute weighing of the material which is delivered from a much larger reservoir of the metal material. The partial quantity which is branched off from the larger quantity is collected in a smaller vessel and will probably not be as accurate as the partial quantities poured into the casting molds. However, this inaccuracy is not important for the absolute weighing of the tap quantity which constitutes the main phase of the method. The two or three times greater larger quantity should be chosen in anamount in accordance with the length of the cycling times of the casting wheel operation and the occurring heat losses.

Each of the quantities are delivered in succession from the furnace to a large size vessel, and from the large size vessel to a smaller size vessel associated directly with each casting wheel by operating a tilting mechanism for effecting the pouring of the melt from one vessel to the other and from the small size vessel to the mold. The invention provides for a control impulse for setting the angle of inclination of the tilt of each vessel and the duration of the tilt as precise as possible. This is favored by keeping the center of gravity of the respective vessels, when in a horizontal position, almost stationary while transporting a partial quantity to be poured or a quantity to be transported. Therefore, no moment develops which could influence the accelerating or decelerating forces.

The apparatus of the invention includes a smelting furnace which is mounted for tilting in order to effect the tapping thereof. The weight of the large size collecting vessel arranged in association with the smelting furnace, including the casting metal which is contained therein, is measured by means of force analyzers, upon which the vessel is supported. A particularly favorable arrangement is obtained by at least two collecting vessels of greatly differing pay load which are disposed between the smelting furnace and one or more casting wheels. The large collecting vessel receives the metal from the smelting furnace which is periodically tapped. A smaller collecting vessel is associated with each casting wheel and serves as an intermediate holder or transporter for the nominal quantity which is obtained by weighing the volume tapped for pouring into a single casting mold. If the heat balance permits, or if additional heating measures for the collecting vessels are considered, several vessels of successively smaller size may be disposed between the smelting furnace and the casting wheels. The transfer error from the collecting vessel to the final vessel for filling each mold becomes smaller and smaller because the volumes collected are decreasing and the respective motions of the smaller vessels for transferring can be executed more precisely.

The motion of the center of gravity of the smelted mass exerts influences upon the accelerating and decelerating forces. in the invention this is avoided by the use of collecting vessels for each stage which are mounted on pivotal frames for easy pivotal movement and which are lined with masonry material topermit the retention of heat and the heating of the melt therein. Each vessel is advantageously supported on a column which is arranged beneath the tilting frame. The column is supported on a force analyzer and sustained in an upright position by rod elements which are pivoted to the frame and to the column and which are arranged around its circumference to hold it in a uniform position. The suspension of the individual collecting vessels on the column permits vertical motion only.

Consequently, the weight rests free of transverse forces on the base area. Movements in a horizontal direction during the pouring operation or while refilling are impossible. The attitude of the vessel always remains unchanged. A tilting drive however, is connected to each vessel and it comprises a fluid pressure operated piston and cylinder which is linked to the vessel and to the supporting frame. in this manner the tilting drive is mobile and participates in the vertical motions possible during the weighing. Accurate weighing is further accomplished by a single force analyzer disposed under the column.

The apparatus also advantageously includes a tilting frame which comprises two side yoke members which are pivotally supported centrally on pivot pins in the tilting drive and which also includes one or more cross members providing a cradle for receiving each vessel.

The invention advantages may be expanded and improved by arranging a much larger size vessel between the small vessel at each casting mold and the tapping mechanism for directing the melt from the smelting furnace. Such large vessels, in accordance with the invention, are also supported on force analyzers and they may advantageously have two pouring spouts in order to facilitate the filling of two separate smaller size vessels arranged alongside a respective spout and adjacent each respective casting wheel.

The invention is further applicable to casting equipment of the most varied types. By disposing the large volume collecting vessel between the two casting wheels and the small collecting vessels which are provided for pouring into each casting wheel, it is possible to pour the metal into one casting wheel while the other small vessel is being filled from the larger vessel. From the standpoint of heat economy the casting metal remains in the big collecting vessel for only a short period of time. The heat losses are therefor accordingly low. Additional heaters of course may be provided with each vessel as desired.

According, it is an object of the invention to provide an improved method for the accurate weight casting of metal plates and in particular of the weight casting of copper anode plates in which the liquid casting metal is tapped from the smelting furnace, comprising directing melt material into a small size vessel and determining the weight of the metal material which is to be formed into the metal plates while it is in the small vessel and as it is being poured into the casting mold regardless of the actual weight of the previously cast metal plate by weighing an absolutely determinable partial quantity from a total quantity amounting to two or three times the partial quantity.

A further object of the invention is to provide a method for the accurate weight casting of metal plates which comprises delivering large size quantities of metal material into a large vessel and selectively pouring from the large vessel into a smaller vessel which is arranged for pouring directly into a casting mold and wherein the weight of the metal plates which are to be cast is to be determined prior to the pouring of the casting metal into the casting mold and irrespective of the actual weight of the previously cast metal plate by weighing out an absolutely determinable partial quantity by pouring it from the larger vessel into the smaller vessel.

A further object of the invention is to provide an apparatus for casting which includes at least one casting wheel having a plurality of casting molds thereon which may be indexed pasta filling station and including a small size melt receiving vessel arranged at the filling station and in a position to receive melt material from a supply thereof, said small size vessel being supported on a force analyzer to permit determination of the weight of the melt material which is to be poured into the casting and being supported on a tilt frame having a tilting drive for effecting thepouring at a controlled rate and in a controlled amount.

A further object of the invention is to provide a cast-- ing apparatus which includes a plurality of rotatable casting wheels each having a plurality of casting molds thereon with filling openings arranged adjacent the peripheries which may be indexed past a filling station, the filling station for each casting mold including a force analyzer supporting a tilt frame on which is positioned a small size melt receiving vessel, and further including a supporting frame having a force analyzer for supporting a larger size vessel which may be tilted in order to pour selectively into each of the smaller size vessels, the large size vessel being associated with means for delivering a quantity of melt material thereto.

A further object of the invention is to provide an apparatus for casting particularly anode plates which is simple in design, rugged in construction, and economical to manufacture.

The various features of novelty which characterize the invention are pointed out with particularity in the claims annexed to and forming a part of this specification. For a better understanding of the invention, its operating advantages and specific objects attained by its use, reference should be had to the accompanying drawings and descriptive matter in which there is illustrated and described a preferred embodiment of the invention.

BRIEF DESCRIPTION OF THE DRAWINGS In the drawings:

FIG. I is a perspective view of an apparatus for easting anode plates constructed in accordance with the invention;

FIG. 2 is a vertical sectional view on an enlarged scale of a small size casting vessel and its associated mounting; and

FIG. 3 is a section taken along the line IIIIII of FIG. 2.

GENERAL DESCRIPTION OF THE PREFERRED EMBODIMENT Referring to the drawings in particular, the invention embodied therein comprises a casting apparatus particularly for forming anode plates which includes a smelting furnace l which is rotatably supported to permit it to be selectively oriented for discharging melted casting liquid from a tapping hole or opening 2 into a chute 3 for delivery through a discharge end 4 into a large size collecting vessel generally designated 5. The vessel 5 includes a pouring spout 6 and a pouring spout 7 at respective opposite ends and it is supported in a tilting frame or cradle generally designated 72 which is pivotally supported on journals 54 on a bearing pedestal 53 in a manner permitting the selected downward and upward tilting of each pouring spout 6 and 7 in order to permit selective pouring into one or the other two collecting vessels 8 and 9 which are arranged adjacent the respective spout ends.

' In accordance with a feature of the invention, the actual dosing of the melt material is done from the small vessels 8 and 9 with the vessel 8 being arranged on a tilt stand 22 adjacent a castingwheel l0 and the vessel 8 being arranged on a tilt stand 22' in a position for filling the casting molds l3 and 12, respectively, which are mounted on a casting wheel 11. The casting wheels 10 and 11 have a plurality of casting molds 12 and 13 (only one of which is shown) which may be of different size or shape if desired. The cavities 14 and 15 of the molds 12 and 13, respectively, match the shape of the copper anode plates which are to be formed by the casting device of the present invention. Such copper anode plates which are formed are subsequently processed in an electrolysis bath. While only one casting mold is shown for each casting wheel, the molds are generally distributed in the areas defined between the radial lines 16, 17, 18, 19, and on each casting wheel.

The large collecting vessel 5 has a substantially greater payload capacity than the small collecting vessels 8 and 9 and the capacity of the larger vessel may be approximately 3 /2 tons while the capacity of the small collecting vessel 8 or 9 may be about 600 kp.

As best indicated in FIGS. 2 and 3, the smaller size vessels 8 and 9 include a single pouring spout 24 and have an interior partially circular bottom wall 23 which runs in the tilting direction.

The tilting frame 22 of each small collecting vessel 8 and 9 is supported by a column 25 and it includes tilting bearing 26 which support tilt pins 27 on each side of the vessel. The pins are rigidly attached to the shell 28. A projection 29 is found either on the shell 28 or a cradle 72 for the vessel 8 or 9. A tilting drive 33 includes a fluid pressure operated piston and cylinder combination including a cylinder 34 and a piston 35 having a rod portion which is connected to the projection 29 and to a projection 30 of the frame 22. The base of the column 25 rests on a force analyzer 38 which in turn rests on a foundation 39 which is supported on feet 40 of the mill floor 41. The foundation 39 also supports the frame 42 which comprises several uprights 43 and two superposed rings 44 and 45. Each ring supports a projection 46 and 47 respectively which provide a connection joint along with opposite projections 48 and 49 for articulated rods 59. The rods 59 are arranged at equally spaced locations around the periphery of the column 25 and each is provided with an adjustable turn buckle. The column 25 can thus be centeredin respect to central axis 50 to thereby determine a position of the small collecting vessel 8 or 9 associated therewith. Three rods 59 are arranged in the planes of the brackets 46 and 47, respectively,

The tilting drive for the large collecting vessel 5 is similar to that of the small collecting vessels 8 and 9. The collecting vessels 5 and 8 and 9 all rest in associated cradles 72 and 72' and 72 for the respective vessels 5, 8, and 9 which are constructed with the side members 51 and 52 and the cross members 55. The vessels 5, 8 and 9 are supported without further fastening and engage in their cradle on parts of the pouring spout 24 and around the periphery of the circular portion 23. In the case of the large vessel 5, the cradle 72 is supported on the frame 21 which rests on a frame 56 which in turn rests on several force analyzers 57 and 58 disposed in the corners of the frame. The tilting drive for this vessel is similar to that of the smaller vessels.

The casting operation for the method of the invention is as follows:

Casting metal melt 60 is continuously or intermittently tapped from the smelting furnace 1 in dependence upon the melting situation at the time of operation and in accordance with the operating speed to be effected. The melt is conducted into the collecting vessel 5 through the chute 3. After a sufficient reservoir 'of melt has been collected in the large vessel 5 it may be continuously heated if desired by burners (not shown). The force analyzers 57 and 58 make the content of the large collecting vessel 5 known in as a weight value, for example, kp. A casting metal quantity of approximately 600 kp. is now withdrawn from the largevessel 5 and poured into a respective one of the smaller vessels 8 and 9 by selectively tilting the vessel 5 in order to permit pouring from the spout 6 or 7 as desired. The smaller vessels 8 and 9 may be continuously heated also if desired or necessary.

Pouring from the smaller vessels 8 and 9 into the casting molds 12 or 13 is effected in accordance with the operation of the casting wheels and preferably pouring from one vessel into the associated mold of one casting wheel is carried out when the other casting wheel with its mold is being moved to a place for removal of the individual cast plates. Approximately 200 kp, for example, is poured out of the vessels 9 or 8 during each casting operation. This pouring is effected on the basis of the indication of force analyzers 38 shown in FIG. 2, to measure out exactly 200 kp which is indicated by electrical measuring instruments (not shown). in practice the weighing operation is carried out during the pouring from the small vessel into the casting mold until 200 kp are removed from the vessel. This value can be determined with great accuracy so that the quantity of metal which is poured into the casting mold is also very accurately determined at 200 kp. In such a process it is immaterial whether the content of the collecting vessel 8 or 9 is 600 or 610 kp. It is quite possible that the content may be only 590 kp. Such errors may result by the supply from the large collecting vessel 5 into the smaller vessels. This may be due to the fact that even though the force analyzers 57 and 58 call for the pouring of 200 kp. the acceleration impulse of the tilt drive mechanism was not kept exactly due to the great mass of 3,500 kp. force which is required to accuate the tilting drive. However, since the quantity of the casting metal contained in the small collecting vessels 8 or 9 represents a relatively small mass the errors in delivering the absolute said quantity of 200 kp become decidely smaller. Therefore, when the final quantity is poured out of the smaller vessel this quantity may be more accurately determined and pouring can be carried out until the precise quantity is measured from the total supply of the much smaller vessels 8 and 9. The

method makes it possible to accurately weigh the casting metal for forming the plates without requiring long regulating distances and without any adjusting of the regulating impulse or electrical control devices.

We claim:

1. A method for the accurate weight casting of metal plates, .particularly for supplying melt to an open top mold so that only the accurately determined weight is fed to the mold for each casting operation and, in particular, for casting copper anode plates using weighing means such as force analyzers for pivotally supporting tiltable metallurgical vessels and using a large receiving vessel and at least one small casting mold pouring vessel, comprising pouring the precise quantity of melt required for one anode plate from the smaller vessel after it is filled with a quantity of melt which is 2 to 3 times the quantity of melt required for the single anode plate casting, and thereafter prior to the casting of the next anode plate, filling the smaller vessel with a quantity of melt necessary for one anode plate from the larger vessel from which the pouring is continued until the twice to three times the initial quantity is again attained as determined by weighing the large receiving vessel.

2. A method for the accurate weight casting of metal plates, according to claim 1, including feeding a liquid melt from a melting furnace to the larger vessel and continuously controlling the weight of the melt in the larger vessel so that it is substantially larger than the weight of the melt in the smaller vessel.

3. A method for the accurate weight casting of metal plates, according to claim 2, wherein the difference in weight between the larger and the smaller vessel is controlled. continuously and maintained substantially constant.

4. A method for the accurate weight casting of metal plates, particularly for supplying melt from metallurgical tilting vessels to an open top mold so that only the accurately determined weight is fed to the mold for each casting operation and, in particular, for casting copper anode plates using weighing means such as force analyzers for pivotally supporting the vessels and using a large metallurgical tilting receiving vessel and at least one small metallurgical tilting casting mold pouring vessel, comprising tilting the smaller vessel to pour the precise quantity of melt required for one anode plate from the smaller vessel as determined by weighing the smaller vessel after it is filled with a quantity of melt which is 2 to 3 times the quantity of melt required for the single anode plate casting, and thereafter prior to casting of the next anode plate, filling the smaller vessel with a quantity of melt necessary for one anode plate by tilting the larger vessel to pour the melt into the smaller vessel and continuing the pouring until the 2 to 3 times the initial quantity is again attained as determined by weighing the large receiving vessel. 

1. A method for the accurate weight casting of metal plates, particularly for supplying melt to an open top mold so that only the accurately determined weight is fed to the mold for each casting operation and, in particular, for casting copper anode plates using weighing means such as force analyzers for pivotally supporting tiltable metallurgical vessels and using a large receiving vessel and at least one small casting mold pouring vessel, comprising pouring the precise quantity of melt required for one anode plate from the smaller vessel after it is filled with a quantity of melt which is 2 to 3 times the quantity of melt required for the single anode plate casting, and thereafter prior to the casting of the next anode plate, filling the smaller vessel with a quantity of melt necessary for one anode plate from the larger vessel from which the pouring is continued until the twice to three times the initial quantity is again attained as determined by weighing the large receiving vessel.
 1. A method for the accurate weight casting of metal plates, particularly for supplying melt to an open top mold so that only the accurately determined weight is fed to the mold for each casting operation and, in particular, for casting copper anode plates using weighing means such as force analyzers for pivotally supporting tiltable metallurgical vessels and using a large receiving vessel and at least one small casting mold pouring vessel, comprising pouring the precise quantity of melt required for one anode plate from the smaller vessel after it is filled with a quantity of melt which is 2 to 3 times the quantity of melt required for the single anode plate casting, and thereafter prior to the casting of the next anode plate, filling the smaller vessel with a quantity of melt necessary for one anode plate from the larger vessel from which the pouring is continued until the twice to three times the initial quantity is again attained as determined by weighing the large receiving vessel.
 2. A method for the accurate weight casting of metal plates, according to claim 1, including feeding a liquid melt from a melting furnace to the larger vessel and continuously controlling the weight of the melt in the larger vessel so that it is substantially larger than the weight of the melt in the smaller vessel.
 3. A method for the accurate weight casting of metal plates, according to claim 2, wherein the difference in weight between the larger and the smaller vessel is controlled continuously and maintained substantially constant. 